1. Field of the Invention
The present invention relates to techniques for allocating resources to a user terminal. More particularly, techniques for allocating resources by which a user terminal can control energy and performance thereof during an allocation of resources to the user terminal.
2. Description of the Related Art
Wireless communications relate to technology using electric waves as transmission media of information. Wireless communication systems can easily transmit information regardless of positions of users and thus have gradually expanded their application ranges. Wireless terminals of the wireless communication systems are mobile, portable, and convenient.
Wireless communications can be classified into first generation and second generation. The first generation wireless communications relate to services used in analog wireless terminals in initial wireless communications. The second generation wireless communications relate to services used in digital wireless terminals following the analog wireless terminals. IMT-2000 services recently called next generation mobile communications are referred to as third generation wireless communications. Services providing high quality Internet services through one wireless terminal at a low cost after the third generation wireless communications are referred to as fourth generation wireless communications.
In the first and second generation wireless communications, concepts of fairness of throughput and energy of communication lines transmitting data are not considered. However, resource management algorithms are applied starting from the third generation wireless communications. The resource management algorithms introduce fairness of energy and provide a high transmission rate in the same bandwidth.
However, when the resource management algorithms are applied to third generation wireless communication systems, access points (APs) must know about utility functions of a plurality of wireless terminals, for example, types, protocols, and Quality of Service (QoS), in advance.
The fourth generation wireless communications after the third generation wireless communications relate to ubiquitous and heterogeneous mobile networks. In the fourth generation wireless communications, various types of wireless terminals or different types of networks are connected to one another to interact with one another. Thus, it is not easy to grasp the characteristics of the various types of wireless terminals and there are no methods for allocating resources considering the energy usage of the various types of wireless terminals.
Also, in the fourth generation wireless communications, users do not stay in one type of network but can select desired one of various types of network. Thus, it is difficult to secure compatibility among the various standards used by the respective networks.
As described above, wireless communications have been developed from first and second generation wireless communications to third and fourth generation wireless communications. However, attempts to reduce an amount of energy used by a plurality of wireless terminals result in deterioration of speeds of communication lines due to problems in managing resources of the plurality of wireless terminals. Also, the total amount of energy used increases with an increase in the speeds of the communication lines.